The current boom in green or environmentally friendly technologies has led to renewed interest in solar energy. The fluctuating but invariably high price of oil in recent memory and recent advances in solar energy collection technologies have made it possible for even individuals to supplant their energy supply needs with solar energy. Solar energy farms (known more generically as solar farms) are also increasing in number, some of which are even sending the energy they have collected to the regular electricity utility companies.
One field in which there has not been as much interest or development has been in the efficiency of the solar energy collectors. One would think that it would be useful to have energy efficient solar energy collectors collecting solar energy. Unfortunately, such has not been the case as current solar energy collectors are still using energy inefficient large electric motors.
As is well-known, solar energy systems need to track the sun to maximize their performance. For some solar energy systems which use devices such as parabolic dish, parabolic trough and central tower systems, it is necessary to continuously track the sun throughout the day, while for photovoltaic (PV) cells, it is highly recommended for the PV panels to track the sun for higher efficiency. In the morning at sunrise, the sun has the lowest altitude angle which reaches the maximum at the solar noon and again starts to decrease to the minimum at the sunset. Thus, the solar collector (dish/panel) is at almost vertical position in the morning and slowly moves toward a near horizontal position by the solar noon and then slowly returns to the vertical position by the sunset. As the sun changes its position very slowly, the movement of the solar collector should also be very slow i.e. a movement of a few centimeters every few minutes.
Currently, high power motors are used to move the solar collectors. In some cases actuators have also been used but they are limited by their stroke length. As the solar collector moves from vertical to the horizontal position, the motor has to push against the collector weight. However, as the solar collector moves from the horizontal to vertical position, the weight of the solar collector provides additional force which pushes the solar collector down. In such situations, the motor may have to counterbalance the weight for controlled and precise small movements. Since the motor and the gearbox have to be attached very close to the axis of rotation of the solar collector, significantly large torque forces are required to move the solar collector from vertical towards the horizontal position. As well, large braking torque forces are required when the dish moves from horizontal towards vertical position.
Due to the significant power requirement that the above techniques require, some companies are using light weight materials such as fibreglass for dishes or solar collectors. However, such materials are expensive and also have major issues with durability. In particular, these materials are not ideal for withstanding wind forces. When a receiver is added to a parabolic dish system, the load that a motor has to move is further increased. For such cases, larger motors are required.
All of the above means that larger motors are currently used to counteract and counterbalance the weight of the solar panel/solar dish assembly. Because of the need for small, precise movements needed to track the sun throughout the day, large torque forces are required, necessitating larger energy consumption.
Another issue with current solar energy collection systems relates to the need to track the sun. Current systems use computers and dedicated hardware to continuously track the position of the sun and to continuously adjust the position of the solar panels/solar dishes to obtain the most efficient exposure to the sun. Current computer controlled systems can easily track the sun for any given day once the latitude and longitude of the location of the solar collection system is entered. As can be imagined, such computer controlled systems can be bulky and quite expensive. As well, such systems can be problematic as any errors in the entry of the longitude and latitude of the location of the solar collection system can throw off the computer's calculations, leading to less than optimal exposure to the sun of the solar panel/solar dish.
Based on the above, there is therefore a need for systems and devices that mitigate if not overcome the drawbacks of the prior art. Current systems are energy inefficient when it comes to the motors controlling the tilting of the solar collector and current solar tracking technologies require high precision entries as well as expensive equipment.